Propeller-type turbine or pump



Dec. 11, 1928.

L. F. MOODY PROPELLER TYPE TURBINE OR PUMP Filed July 12, 1926 2Sheets-Sheet 1 anoantoz Ill/1100a? Zen i4 351 M45 Stigma/54 Dec. 11,1928.

L. F. MOODY PROPELLER TYPE TURBINE OR PUMP.

Filed July 12, 1926 2 Sheets-Sheet 2 m w W u 0 m m E F. f i .w W 1% 6 mZ fl WW 8 My MM 2 w ,//,v////// V/ P\ a a g ,,/M//

Patented Dec. 11, 1928.

UNITED STATES :PATENT' OFFlCE.

LEWIS FERRY MOODY, OF PHIIIAD ELPHIA, PENNSYLVANIA.

PBOPELLEB-TYPE TUERBINE OB PUMP.

Application filed July 12, 1926. Serial N0. 121,787.

surrounding wall to allow clearance between the periphery of the runnerand the wall. This clearance which in some installations, usually of thelarger propeller type runners, is considerable, causes loss ofefliciency. The

. clearance must be suflicient to prevent the runner blades touching thesurrounding wall in case there is any vibration, in perfect alignment orirregularity of construction, or in case the thrust bearing should allowthe runner to drop a small distance or in case a rubber or wood linedbearing is used which may permit lateral displacement of the runner. Theobject of this invention is to provide means for reducing the clearancebetween the periphery of the runner and the outer wall so as to increasethe efliciency and to improve the operation of the turbine.

A further obj ect'of the invention is to provide means for preventingbreakage of the runner blades when any foreign material or obstructionvpasses within the clearance between the runner and the outer wall, or ifthe blades should touch the wall.

Further objects and advantages of the invention will be apparent byreference to the following specification and accompanying drawings, inwhich Fig. 1 is a plan view on section A-A of the turbine shown in Fig.2 embodying the invention;

Fig. 2 is an enlarged sectional elevation through a hydraulic turbineshowing the runner and the surrounding parts;

Fig. 3 is an enlarged sectional view of an edge or tip of a runnerblade;

Figs. 4 and 5 show other arrangements for fastening thematerial to therunner tips;

Fig. 6 is an enlarged sectional elevation through a hydraulic turbineshowing the runner and the surrounding parts with an adjliistable rubberlined ring in the stationary wa Fig. 7 is an enlarged sectionalelevation showmg an adjustable metal ring in the stationar wall andrunner blades tipped with yielda le material.

directed to the runner from the volute casmg 12 through the stay vanes13 and guide vanes 14. The tip of the blades are provided with a stripof rubber or other material of a relativel soft or ielding nature 15which is cemente molded vulcanized or mechanically fastened to themetal. In Fig. 3 the metal tip of the blade 11 is provided with a flange16, around which the rubber is secured so as to provide the blade with acontinuous smooth surface, the rubber being ground to merge with themetal surface.

After the rubber strip is secured to the tip of the blade by cementing,molding or vulcanizing, the rubber is further ground down to fit theclearance space, substantially eliminating the clearance between therunner and the outer casting 17 The grinding is accom; plished with theordinary portable grinder, the runner mounted for rotation on a boringmill I or rotating table. The blades are ground to fit the requiredshape of the outer casting, which is usually conical or cylindrical orformed with a circular arc in meridian section.

The rubber tip of the blades closely spaced from the casting 17 willyield if for any reason foreign material, obstructions or trash entersthe turbine casing. The obstruction if small enough to enter theclearance space will pass through to the draft tube without causingbreakage of the runner blade. Tne use of rubber tipped runner bladesincreases the efficiency because it makes possible the provision of verysmall clearance between'thc runner blades and the surrounding wall, andtherefore permits little leakage of water to pass between the runner andthe stationary wall. The leakage which occurs when there is considerableclearance is objectionable not only on account of the direct loss ofuseful flow, but also from the disturbance which it causes in theadjacent flow near the bladetips.

Fig. 4 shows another modification of the invention in which the yieldingmaterial 15 is dovetailed into the tip of the runner blade and projectsbeyond the metal portion of the blade to form a close seal between thesurrounding wall and the blade. I

Fig. 5 shows a further modification in which the strip of yieldingmaterial 15 is held mechanically in place in the tips of the runnerblades. This strip may be made of rubber or material of like nature ormight be made of wood or of soft metal, such' as lead or babbitt. Themetal should be soft enough llvi that it would wear down if therunnertouched the surrounding wall without scorlng or -1njuring the latterinany we The blades 11 are provided with' removable plates 18 which areheld in lace by means of screws 19 tapped into the b ades.

In Fig. 6 a modification ofthe invention is shown wherein an adjustablering 20 having a rubber lining 21 is set into a circular open ing 22 inthe casting 17 The ring 20 is held in position b screws or bolts 28tapped into the casting 1 at 24. These bolts are in recesses 25 filledwith type metal finished flush with the wall surface. If the ring 20 orthe blade tips become worn or if the ring needs adjustment to decreasethe clearance between the wall and the runner blades 11, the type videdwith a yielding means at its tip for reducin clearance between therunner and the walfi 5. In a hydraulic turbine, the combination with anouter stationary wall, of a 'runner having a central hub ortion and aplurality .of blades, and means or adjusting the clearmetal 26 can bemelted out of the recesses, the

screws or bolts 28 loosened to permit the ring 20 to be raised a smallamount, and the bolts 28 again made tight and the recesses 25 refilledwith type metal. The slightly tapering or conical outer surface of ring20 will thus be moved toward the runner blades to decrease theclearance. By these means the clearance between the casing and runner ismade adjustable.

Fig. 7 shows a modification wherein the blade tips are provided withrubber and the casting 17 is provided with an adjustable clearance ring27.

While the invention is illustrated and described more particularly withreference to propeller type turbines, the invention is not.

confined thereto, but is applicable to pumps having unshrouded impellersor any other uses or modificationswithin the scope of the appendedclaims.

I claim 1. In a runner for a turbine or pump the combination with acentral hub portion, of a circumferential series of unshrouded bladesthereon normally having a fixed relation thereto, each blade beingprovided with yielding means at its tip for reducing clearance andincreasing the efliciency of the runner.

2. In a runner for a turbine or pump the combination with a central hubportion, of a circumferential series of unshrouded blades thereon,normally having a fixed relation thereto, each blade being provided witha rubber tip for reducing clearance-and increasing the efiiciency of therunner.

3. In a runner for a turbine or pump the combination with a'central hubportion, of a plurality of blades thereon, each blade being flanged atits tip, and a rubber strip secured to said flange for reducingclearance and increasing the efliciency of the runner.

4. In a hydraulic turbine the combination with an outer stationary Wall,of a runner surrounded by said wall having a central hub portion and aplurality of unshrouded blades thereon having normally an immovablerelation thereto, each blade being proance bet-ween said outer wall andthe runner blades.

6. In a hydraulic turbine the combination with an outer stationary wall,of a runner surrounded by said wall havin acentral hub portion and aplurality of blades all disposed substantially in a plane normal to therunner axis, said blades having normally an immovable relation to saidhub and yielding material for the clearance between said outer wall andthe runner blades.

7. In a rotary hydraulic machine the combination with an outerstationary wall, of a runner having a central hub ortion and a pluralityof blades all dispose substantially in a plane normal to the runneraxis, said blades having normally an immovable relation to said hub, theclearance space between said wall and said runner blades being providedon one' side with a rigid material and on 1the opposite side with ayieldable mater1a 8. In a rotary hydraulic machine the combination withan outer stationary wall, of a runner having a central hub portion and aplurality of blades, the clearance space between said wall and saidrunner blades being provided on one side with a rigid material and onthe opposite side with a yieldable material, and means for adjusting theclearance between said wall and said blades.

9. In a rotary hydraulic machine a runner having a plurality ofunshrouded blades and a circular and concentric stationary surroundinwall,'said blades at their tips being closely isposed to said wall withsmall running clearance therebetween and eachv blade being provided withyieldable means at its tip to permit the provision of said smallbination of a runner having a plurality of unshrouded blades and astationary surrounding wall, said blades at their tips being closelydisposed to said wall with small running clearance therebetween, saidwall having a generally conical shape smaller at one end than the other,and means for effecting relative axial adjustment between said runnerand the portion of said wall adjacent the runner to provide adjustmentof the clearance between said wall and runner.

11. In a rotary hydraulic machine, the combination of a runner havin aplurality of unshrouded blades and a circufir and concentric stationarysurrounding wall, said blades at their tips being closely disposed tosaid wall with small running clearance therebetween, the clearance s acebetween the blade tips and stationary wa lhavingyieldable material onone side thereof and r1g1d material on the other side.- v

12. In a rotary hydraulic machine a runner having a plurality ofunshrouded blades having during normal operation a fixed relation to therunner hub and an outer stationary wall extending in an axial directionand coaxial with said runner, said blades at their tips being disposedclosely to said wallwith small running clearance therebetween, and eachblade being provided with yieldable means at its tip to permit theprovision of said small clearance.

13. In a rotary hydraulic machine the combination with a runner ofgenerally axial flow type having unshrouded blades having during normaloperation a fixed relation to the runner hub and a continuous outercircular wall surrounding said runner and slightly spaced therefrom toprovide a small running clearance therebetween, said blades at theirtips engaging said wall with small running clearance, said blades beingprovided with yieldable material at the tips to permit the provision ofsaid small clearance.

14. In a hydraulic turbine or pump the combination with a central hubportion of a circular series of unshrouded blades thereon of relativelyunyielding material, said blades having a radially fixed position withrespect to said hub during normal operation of the runner and each bladebeing provided with a different material at its tip forreducingclearanceand increasing the efliciency of the runner.

15. In a hydraulic turbine or pump the combination with a central hubportion of a circular series of unshrouded blades thereon of relativelyun ieldin materiahsaid blades havin a radial fixe position withvre'spectto said hub during normal operation of the runner and each blade beingprovided with a yielding material at its tip for reducing clearance andincreasing the efficiency of the runner.

16. In a hydraulic turbine orpump thev combination with a central hubportion of a circular series of unshrouded blades thereon of relativelyunyieldin material, said blades having a radially fixe position withrespect to said hub during normal operation of the runner and each bladebeing provided with a relatively soft material at 1ts tip for reducingclearance and increasing the efliciency of the runner. 1

' 17. The combination in a hydraulic turbine or pump comprising a runnerhaving a hub and a plurality of unshrouded blades all lyingsubstantially in a plane normal to the runner axis and having duringnormal operation a radially fixed position with respect to said hub, astationary wall surrounding said blades which at their tips are. closelydis- LEWIS FERRY MOODY.

CERTIIFIGATE 0F CORRECTIIQN.

Patent No. 1,694,481.

Granted December n, 1928, m'

LEWlS FERRY MOODY.

It is hereby certified that error appears inv the printed specificationof the above numbered patent requiring correction as follows: Page 1,line 14, for the words in perfect" read "imperfect"; and that the saidLetters Patents should be read with this correction therein that thesame may conform to the record of the case in the Patent Office.

Signed and sealed this 12th day of March, A. D. 1929.

(sen

. M. J. Moore, Acting Commissioner of Patents.

